An amplifier device has an amplifier circuit, an energy supply device, a switching matrix and a control device. A radio-frequency, low-energy signal pulse can be amplified into a high-energy power pulse by the amplifier circuit. The amplifier circuit is supplied with electrical energy by the energy supply device. The energy supply device has a number of electrical energy sources that are separated in terms of potential relative to one another in a state in which they are not connected to the amplifier circuit. The electrical energy sources can be selectively connected to the amplifier circuit by the switching matrix. The switching state of the switching matrix can be dynamically set for this purpose by the control device.
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1. An amplifier device comprising:
an amplifier circuit having an input configured to receive a radio-frequency, low-energy signal pulse, which is amplified by said amplifier circuit into a high-energy power pulse at an output of the amplifier circuit;
an energy supply device that supplies said amplifier circuit with electrical energy, said energy supply device comprising a plurality of electrical energy sources;
a switching matrix connected between the energy sources of said energy supply device and said amplifier circuit;
a control device connected to said switching matrix that operates said switching matrix to selectively connect one or more of said energy sources to said amplifier circuit; and
said energy sources in said energy supply device being separated in terms of voltage from each other in a state in which the energy sources are not connected to the amplifier circuit.
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1. Field of the Invention
The present invention concerns an amplifier device having an amplifier circuit and an energy supply device. A radio-frequency, low-energy signal pulse can be amplified into a power pulse by the amplifier circuit. The amplifier circuit is supplied with electrical energy by the energy supply device.
2. Description of the Prior Art
Amplifier devices of the above type are generally known. They are in particular used for generation of transmission pulses for RF transmission coils in magnetic resonance systems. Other applications, for example in radar systems, are also possible.
In magnetic resonance systems the requirements for the power pulses to be output vary to a significant extent. This applies both for the duration of an individual pulse and for its maximum power and its average power as well as for the required currents and voltages.
It is of course possible to design the amplifier circuit and the energy supply device such that they operate properly in all operating states even though the energy supply device is permanently connected to the amplifier circuit, and the output voltage emitted by the energy supply device is kept constant, or optimally constant. In practice, however, this approach leads to significant power losses in the amplifier circuit in many operating situations. The power losses are significantly higher than when the amplifier circuit is operated with voltage values that are adapted to the respective operating state of the amplifier circuit.
The adaptation of the voltage value leads to a reduction of the power loss that occurs in the amplifier circuit, but in many cases it leads to significant power losses in the energy supply device. The problem is thus only shifted, but is not solved.
An amplifier device of the aforementioned type, in which the energy source is fashioned as a primary energy source that can be connected to the amplifier circuit via a primary coil and a secondary coil of a transformer, is known from U.S. Pat. No. 3,319,175. The secondary coil has multiple taps so that the voltage that is applied to the amplifier circuit can be adjusted as needed.
An object of the present invention is to further develop an amplifier device of the aforementioned type such that it can be manufactured and efficiently operated more cost-effectively. The amplifier device should in as a whole exhibit only a relatively small power loss.
The object is achieved by an amplifier device according to the invention, wherein the energy supply device is formed by a number of energy sources that are separated (isolated) in terms of potential relative to one another in a state in which they are not connected to the amplifier circuit. The amplifier device furthermore has a switching matrix by which the electrical energy sources can be connected to the amplifier circuit. The amplifier device has a control device from which a switching state of the switching matrix can be dynamically set.
Based on the inventive solution it is possible to connect the individual energy sources to the amplifier circuit without instabilities, clock couplings or even unwanted surprise effects being able to occur.
The switching matrix is advantageously fashioned and can be controlled by the control device such that at least one of the energy sources can be individually connected to the amplifier circuit. It is thereby possible to connect only one of the energy sources to the amplifier circuit at a specific point in time. Such a connection of a single energy source is particularly useful, when the power pulse to be output exhibits relatively low voltage and/or current requirements.
It is possible for only one of the energy sources to be available for individual connection to the amplifier circuit. Alternatively, it is possible to select which of the energy sources is connected to the amplifier circuit. This latter approach can be particularly useful and sufficient when output voltages of the individual energy sources and/or current carrying capacities of the individual energy sources are different from one another. This procedure can also be useful when redundancy should be ensured.
As an alternative or in addition to the individual connection of one energy source to the amplifier circuit, the switching matrix is advantageously fashioned and can be controlled by the control device such that at least two of the energy sources can be simultaneously connected to the amplifier circuit. The amplifier circuit can thereby be supplied with a higher voltage and/or with a higher current.
When the at least two energy sources exhibit substantially identical current carrying capacities, the switching matrix is advantageously fashioned such that the at least two energy sources can be connected in series to the amplifier circuit. As an alternative or in addition to the substantially identical current carrying capacity together with potential isolation, when the at least two energy sources deliver the same output voltages, the switching matrix is advantageously fashioned and can be controlled by the control device such that the at least two energy sources can be connected in parallel with the amplifier circuit.
Each of the energy sources can advantageously be fed from an alternating voltage network (mains) via the secondary coil device of a transformer device (each energy source having its own, individually associated secondary coil) and a rectifier device downstream of the respective secondary coil device. A potential isolation of the energy sources relative to one another this results in a particularly simple manner by this embodiment.
The transformer device is advantageously fashioned as a multi-phase (in particular three-phase) transformer device. A relatively low ripple of the direct voltage emitted by the energy sources thereby results in a simple manner.
The secondary coil devices advantageously interact with a single primary coil device that can be connected with the alternating voltage network. The design of the transformer device is simplified by this measure.
The transformer device advantageously has at least one further secondary coil device via which at least one further device (that is not an electrical energy source that can be connected to the amplifier circuit) can be fed from the alternating voltage network. By this measure it is possible, for example, to provide a single system transformer that generates all voltages required in a larger system. The further secondary coil device can be in terms of potential from the other secondary coil devices. Alternatively, it can be potential-coupled with one (however advantageously not with more than one) of the other secondary coil devices.
Each energy source advantageously has a basic voltage generation device and a voltage adjuster. In this case the voltage adjuster (voltage setter) is arranged between the respective basic voltage generation device and the switching matrix. The respective voltage adjusters can be controlled by the control device such that it adjusts a respective basic voltage delivered by the respective basic voltage generation device to a respective output voltage. The output voltages can be optimally adjusted by this measure, in particular to predetermined desired voltages.
A desired value of the respective output voltage can be rigidly predetermined. Alternatively, the desired value can be parameterizable or variable.
The switching matrix is formed by switching elements. The switching elements can advantageously be controlled by the control device in a potential-isolated manner. Also, no disadvantageous voltage feedback thus results via control of the switching matrix by the control device.
The switching elements can be fashioned as field effect transistors. In this case the energy sources can be connected to the amplifier circuit in a low-loss and low-resistance manner and be separated in a very high-resistance manner from the amplifier circuit.
In a preferred application of the amplifier device, an RF transmission coil of a magnetic resonance system is arranged downstream of the amplifier circuit such that the high-energy power pulse can be fed to the RF transmission coil as a transmission pulse.
In the course of acquisition of a raw data sequence of the magnetic resonance system, a low-energy pulse (signal pulse) p is fed to an amplifier device 7 of the radio-frequency system 3 at specific points in time. Each low-energy pulse p exhibits a predetermined time curve that can be different from pulse p to pulse p. A longer pulse pause lies between every two low-energy pulses p. The amplifier device 7 amplifies the low-energy pulse p fed to it and thus generates a corresponding power pulse P. The amplifier device 7 feeds the power pulse P to an RF transmission coil 8 of the radio-frequency system 3 as a transmission pulse. The embodiment of the amplifier device 7 is the main subject of the present invention. This is subsequently explained in detail in connection with
According to
The signal pulse p in the is radio-frequency range. It normally exhibits a frequency f that lies between 8 and 300 MHz. Sometimes the frequency f can be even higher.
The amplifier device 7 furthermore comprises an energy supply device 10. The amplifier circuit 9 can be supplied with electrical energy by means of the energy supply device 10. The energy supply device 10 has a number of electrical energy sources 11-1 through 11-4.
A switching matrix 12 is arranged between the energy supply device 10 and the amplifier circuit 9. The switching matrix 12 is likewise a component of the amplifier device 7. The electrical energy sources 11-1 through 11-4 can be connected to the amplifier circuit 9 by means of the switching matrix 12.
The amplifier device 7 furthermore has a control device 13. A switching state Z of the switching matrix 12 can be dynamically adjusted by the control device 13. The control device 13 allows selection of which of the energy sources 11-1 through 11-4 are connected to the amplifier circuit 9, and adjustment of the energy source or sources that are connected.
Information I about the next power pulse P to be output is normally fed to the control device 13. Using the information I the control device 13 then determines the switching state Z and correspondingly controls the switching matrix 12. As an alternative or in addition to the determination of the switching state Z using the information I, the control device 13 can determine the switching state Z dependent on output voltages U1 through U4 which the energy sources 11-1 through 11-4 currently exhibit.
The switching state Z is normally set before the output of the respective power pulse P and maintained during the output of the power pulse P. It is alternatively possible to change the switching state Z during the output of the power pulse P.
The switching state Z can be varied. For example, it is possible that the control device 13 connects a single one of the energy sources 11-1 through 11-4 or multiple energy sources 11-1 through 11-4 to the amplifier circuit 9. In this case the control device 13 also determines which of the energy sources 11-1 through 11-4 are connected to the amplifier circuit 9 and in which connection (parallel, in series, combined) this possibly ensues. This is discussed again later in connection with
According to
In the simplest case, the secondary coil devices 14-1 through 14-4 are fashioned single-phase. In this case a single secondary coil is present per secondary coil device 14-1 through 14-4. In the simplest case the rectifier devices 17-1 through 17-4 are fashioned as simple half-wave rectifiers that comprise a single diode. Although this embodiment is possible, it is not preferred.
At least the rectifier devices 17-1 through 17-4 are advantageously fashioned as bridge rectifiers. Furthermore, the transformer device 15 is advantageously fashioned as a multi-phase transformer device 15. The design as a three-phase transformer device 15 (rotary current transformer) is in particular possible. In the event that the transformer device 15 is a multi-phase transformer device 15, the direct output signal of the rectifier devices 17-1 through 17-4 already exhibits a significantly reduced ripple. The ripple can possibly be even further reduced by capacitors 18-1 through 18-4 that are arranged downstream of the rectifier devices 17-1 through 17-4.
According to
The interaction of the secondary coil devices 14-1 through 14-4 with a single common primary coil device 19 is preferable but not mandatory. Alternatively, the secondary coil devices 14-1 through 14-4 could interact individually or in groups with a separate, respective primary coil device 19.
According to
Each energy source 11-1 through 11-5 has a basic voltage generation device. In the embodiment according to
The output voltages U1 through U4 are detected by corresponding measurement devices 21 and fed to the control device 13. The control device 13 controls voltage adjusters 22-1 through 22-4 that are arranged between the respective basic voltage generation device and the switching matrix 12. Based on the control by the control device 13, the voltage adjusters 22-1 through 22-4 adjust the basic voltage to the respective output voltage U1 through U4.
The embodiment from
According to
Combinations of the described procedures are also possible. For example, a series circuit of the energy sources 11-1 and 11-2 on the one hand and of the energy sources 11-3 and 11-4 on the other side can thus be formed by controlling two switching elements 23 of the third group G3. The two series circuits of two energy sources 11-1 through 11-4 per series circuit can be connected in parallel with the amplifier circuit 9 by controlling two switching elements 23 per each of the first and second groups G1, G2.
The circumstance that the switching elements 23 can be controlled by the control device 13 should not detract from the existing potential freedom of the energy sources 11-1 through 11-4. For this reason the switching elements 23 can advantageously be controlled in a potential-separated manner by the control device 13. For example, the switching elements 23 according to
The throughput resistance from the energy sources 11-1 through 11-4 to the amplifier circuit 9 or, respectively, the energy sources 11-1 through 11-4 among one another should be very small or very large depending on whether the respective switching element 23 is connected through. Furthermore, the control should be able to occur with as little power loss as possible. The switching elements 23 are therefore advantageously fashioned as field effect transistors according to
The present invention was explained in the preceding in connection with four energy sources 11-1 through 11-4, but the number of energy sources 11-1 through 11-4 can clearly be arbitrarily selected when it is at least two. For example, 3, 5, 6, 8, 10, 15, 20, . . . energy sources 11-1 through 11-4 can be present.
The inventive amplifier device 7 can in particular be operated independently of the number of energy sources 11-1 through 11-4 that are connected to the amplifier circuit 9, and independently of which type of connection (parallel, in series, combined). The stability of the operation is also ensured independently of the form and (within limits) the power requirement of the power pulses P.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
Kroeckel, Horst, Albrecht, Adam
Patent | Priority | Assignee | Title |
8049368, | Jun 12 2008 | Seiko Epson Corporation | Load driving circuit and load driving method |
9250641, | Jun 12 2008 | Seiko Epson Corporation | Load driving circuit and load driving method |
9341688, | Nov 14 2011 | SIEMENS HEALTHINEERS AG | MRT system with a magnetic coil and method for manufacturing a circuit arrangement for switching a coil current |
Patent | Priority | Assignee | Title |
3319175, | |||
5565779, | Oct 21 1993 | The Regents of the University of California | MRI front end apparatus and method of operation |
6788151, | Feb 06 2002 | Lucent Technologies, INC | Variable output power supply |
7457598, | Apr 01 2004 | Harman Becker Automotive Systems GmbH | Signal amplifier system for a broadcast receiver |
7532067, | Sep 29 2006 | Siemens Healthcare GmbH | Amplifier device with adjustable supply voltage |
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Dec 17 2007 | ALBRECHT, ADAM | Siemens Aktiengesellschaft | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 020610 | /0755 | |
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